The invention is based in particular on an adjustable hydraulic machine of the axial piston type as known exemplarily from DE 10 2005 060 960 B3. This hydraulic machine comprises a cylinder block mounted on a valve segment displaceable in a housing. The valve segment is connected via a rod to a control piston whose movement is electrically controllable by a proportional solenoid. The displacement volume of the hydraulic machine is adjustable by the movement of the valve segment together with the cylinder block.
DE 101 19 236 C1 discloses a largely similar hydraulic machine, whose movement of the displacement element designed as a valve segment together with the cylinder block is limited by adjustment screws at the housing. The adjustment screws form limit stops for the valve segment which define the end positions of displacement.
The hydraulic machines according to the state of the art are usually operated by an electronic control unit which is used to set the displacement of the control piston and therefore the displacement volume of the hydraulic machine. Here it should be considered that the range of displacement of the displacement element together with the cylinder block is limited between two end positions. In fact, the actual position of the control piston is detectable by sensors as exemplarily disclosed in DE 101 19 236 C1, however, there is no reliable and exact indication of an end position of displacement being reached, which can be used by the control unit. Moreover, the use of such sensors incurs increased costs, particularly as these sensors must be calibrated in each hydraulic machine.